Does LAM-MPI optimize a Send whose destination is the local node (and the
corresponding Recv whose source is the local node)? How?
That is, if I have:
if (myID==0)
for (i=1;i<100;i++)
MPI_Send(&x, ..., tag, dest, ...)
else
for (i=1;i<100;i++)
MPI_Recv(&y, ..., ANY_TAG,source, ...)
and in some cases, the send is to the local node, the recv is from local
node.
This may happen if the data distribution is irregular and the source and
destination is not known until run time. If it is local, there is no need
to copy x to the buffer and then copy the buffer to y. But can the LAM-MPI
compiler/runtime detect that, and make approopriate action, like converting
the Send/Recv to simply y=x?
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